The Function of the Endocrine System (AQA AS Psychology)

Glands & hormones

• A hormone is a chemical that is secreted by the endocrine glands into the bloodstream which then distributes it around the body

• The major gland which regulates hormones is the pituitary gland, located at the base of the hypothalamus in the brain

• Hormones act slowly (unlike neurotransmitters which act fast) and may take years to fully have an effect, e.g.

  • puberty involves the slow release of testosterone (males) and oestrogen (females)

    • Testosterone and oestrogen are, respectively, the male and female sex hormones which control primary and secondary sexual characteristics 

    • Testosterone and oestrogen also regulate key milestones such as puberty, sperm production (testosterone), the menstrual cycle and menopause (oestrogen)

• Hormones have different effects on the body and behaviour, depending on the nature of the hormone itself

• The following hormones are secreted by the pituitary gland include:

  • Adrenocorticotropic Hormone (ACTH) - triggers the adrenal glands to produce cortisol and androgens (a group of male sex hormones)

  • Follicle-stimulating hormone - plays a role in sexual development and reproduction in both males and females

  • Luteinising hormone - encourages ovulation and hormones needed to support pregnancy

  • Oxytocin - secreted during childbirth, encourages attachment between mother and baby

  • Thyroid-stimulating hormone - triggers the release of thyroxine, which regulates the body's metabolism

• The following hormones are secreted by other glands under the control of the pituitary gland:

  • Melatonin - regulates the sleep/wake cycle and is sensitive to light levels

  • Cortisol - the stress hormone, secreted during times of anxiety, tension

  • Adrenaline - active during the fight-or-flight response to danger

  • Insulin - helps blood sugar enter the body's cells so it can be used for energy